The present invention generally relates to a magnetic head, and more particularly to a miniaturized magnetic head which maintains a good contact with a disk and has an effect of reducing power consumption for a disk driving motor.
In recent years, miniaturization in size and thickness of personal computers has advanced. These computers are called notebook type or book type computers, and further development for miniaturization has been progressed. These computers need to be provided with a memory apparatus which stores programs and data. Magnetic disk apparatuses are widely used in personal computers. In the notebook type or book type computers, for example, magnetic disk apparatuses are generally used as a memory apparatus. Since the space provided for the magnetic apparatus is limited in these types of computers, development of a further miniaturized magnetic disk apparatus is required.
As magnetic disk apparatuses have been miniaturized, the magnetic head used in the magnetic apparatuses are required to be further miniaturized. Additionally, in a portable computer, a rechargeable battery is used for power supply, and usable time is limited due to the limited capacity of the battery. Among parts that consume electric power, the disk driving motor is the major unit responsible for the consumption of electric power. Accordingly, if usage of the disk driving motor increases, the usable time of the computer is shortened.
A conventional magnetic head used for a magnetic disk apparatus, as shown in FIGS. 1A and 1B, comprises a slider 1 and a head core 2. The slider 1 and the head core 2 are integrally formed in one piece. A groove 3, which extends in the tangential direction of disk rotation, is provided on a sliding surface of the slider 1. The groove 3 is positioned in the center of the sliding surface of the magnetic head, and the width L of the groove is approximately 0.7 mm to 1.2 mm.
Generally, two magnetic heads are provided in a single magnetic disk apparatus so that recording of information and reproducing of information can be performed at either surface of a disk. FIG. 2 is a side view of this type of head structure in a state where the heads contact both sides of a disk. In the figure, each of two magnetic heads 5 is slidably contacting respectively either surface 4a or 4b of a magnetic disk 4. As the magnetic disk 4 rotates, an air flow is generated inside the groove 3 that results in generation of a negative pressure inside the groove 3. The negative pressure exerts an attracting force on the magnetic head toward the surface 4a or 4b of the magnetic disk 4. This attracting force enables stabilization of the head-touch (degree of head contact) of the magnetic head 5 with the surface 4a or 4b of the magnetic disk 4.
As the magnetic head 5 is miniaturized, the area of the sliding surface of the magnetic head, which surface contacts and slides on the surface 4a or 4b of the magnetic disk 4, becomes small. In a case where such a miniaturized magnetic head is provided with a head-loading force (a pressing force) equal to a conventional magnetic head, sliding resistance increases and thus the running torque of the disk driving motor is increased.
If the width of the groove 3 of the magnetic head 5 is relatively large as it is in the conventional magnetic head, head-touch of the magnetic head becomes stable, while the running torque (power consumption) is drastically increased. Particularly, in the case of the battery driven apparatus such as a portable personal computer, the energy consumption rate of the battery becomes fast, and thus there is a problem in that the usable time is shortened.
Additionally, if the width of the groove is large, the penetration margin tends to become small. Here, the penetration margin is the tolerance of the position of a magnetic head relative to a magnetic disk in a direction perpendicular to a surface of the magnetic disk required to perform effective recording or reproducing at a signal level higher than a predetermined level. When the penetration margin becomes small due to a movement of the magnetic disk in a direction perpendicular to a surface of the magnetic disk, there may be a problem in that the recording or reproducing level tends to easily decrease.